Adjustable torque tool



July '2; 1957 J.. c. BONNEAU am. 2,797,564

ADJUSTABLE Tomos Tool.

Filed Aug. l11. 1954 IN V EN TOR.

United States This invention .relates .to @an .adjustable :torque...tool

Aand.more;particularly .to such.a..tool.in .whiehthe vtorque appliedtherethrough .for turningtamemhenin one .direction Mmay be z regulatedso .as ,to .prevent tightening tof .a

screw, `ornut, .beyond:acertain,predeterminedrlimit.

further object -is to,.provide. such.a.tool fwliichicantbe `adjusted tovary Ythe .torque .thatmaywhev#applied-@therethrough.

:Further fobjects and advantages .will vvbe more vdearly understood fromAthe,.following -'description .and .accompanying drawings in which:

Fig. l .is -a sectionalplan view-ton linel ,1;-1=:of Fig. 2. Fig. 2 isaside view, l,.partlyin central Vvertical section on line 2 2 of -Fig.l, 'ofa screwdriver embodying the presenuinvention. 1

fFig. 3 is =a-plan-view of-theratchebmember inisai'dttool. Fig. 4 is anenlargedside viewfthepawl member used in said tool.

' Fig. '15 sian-enlarged sideview. foflthef ratchetdmenber.

Fig. 6 is a sectional side view showing a modified form of theinvention.

In the embodiment illustrated, the numeral 5 denotes the handle of thetool and 6 denotes a shank supporting portion which extends therefrom.

The said handle 5 has a threaded axial recess 7 connectingwith aco-axial reduced portion 8 of said recess which connects with an axialbore 9 in the shank portion 6. An annular shoulder 10 is providedbetween the portions 7 and 8 of the axial recess in said handle.

A backing screw 11 is threaded to the wall of the recess 7 and has alongitudinal bore 12 therein which slidably contains a pawl pin 13 thathas a collar 14 and a stem 15 over which there is mounted a thrustspring 16 which is seated against the said collar 14 and projects abovethe top of the backing screw 11.

An adjusting screw 17 is also threaded to the side walls of the recess 7and anchors the upper end of the spring 16.

A shank 18 is rotatably contained within the bore 9 and has at its upperend a ratchet head 19 with an annular row of ratchet teeth 20 thereinwhich are adapted to be engaged by the bore 13. The said teeth areprovided with cam surfaces 21 extending towards one side thereof andwith abrupt walls 22 at their opposite sides.

It will be noted that the ratchet head 19 is of a height substantiallyequal to or slightly less than the depth of the recess portion 8 so thatthe end of the backing screw 11 will abut the annular shoulder 10 andpermit tightening of said screw into position while allowing forsulcient clearance to permit rotation of the head 20 in said recessportion.

In order to lock the adjusting screw 17 into adjusted position, the saidscrew is extended out of the end of the recess 7 and there is provided alock nut in the shape of a cap 23 which is threaded to the extended endof the said adjusting screw and abuts the end of the handle portion 5.

In the modified form shown in Fig. 6, the adjusting s v2-screwsl'kafhasa.shoulder 17b anda reducedheadpor- AV-tion 17-,c.

eTheflockgnut.Z3-ads,threaded to the same `thread `7 `as.art/headjusting screw and i has a recess .2S-b which .receives 5.thehead .'17.c. The `end of .said Anut 23-a engages the shoulder l'7-'bto lock the adjusting screw -in adjusted position. f Y

The .operation of .my 'improved adjustabletorque. tool: is .as follows:Y

,Ille desiredztarnount .of .torqueallowed forturning Vasscrew.or..nut.is/obtained by `rst rot-atingthe .screw .17 to varythe,pressure .of thefspring 16 .uponthe .pawl .13 .and .therebykvarying,the kamount of pressure which :is applied Lby .thesaidpawl ontotheratchet teeth20 .and 15 .the .torquetthatismequired Ytorcausethefpawl 13 to slide up the 'cam .surfaces l21,and therebyv limitthe ,amount'of :torque that .canfbeapplied upon. the shank =18,byrotation ofihe-,handleQportion j When'fIhe ,toolfisfused for rotating.ascrew v.or nut,

20 .the ,handle isfurned Vuntil the shank .18V stops turning 4andtheproper` amount oftorque`will then have beenapplied. .IErth'errotation`of thehandle will not .rotate the shank '.138 lhiit .willmerely. causeescapement between .the teeth 20.andttliepawl,'13,

25 The straightwall portion 22 ,of saidteethwill .provide sa ,positive.connection `between the, said .shank and -handle l so as topermitturning=of.,the.screw .or-nutin-a. left hand .direction .-when`itis.de'sired to,`1oo'sen.,the Asaid 4screw..or nut-'.ardenoflimit to.the torque applied thereto lin :that

.directioniis wanted.

"It will be noted fromFig. Y1 that the end,o'f.;the,paw1-13issemi-spherical ,so that. it will properlyengage .with the teeth222inany-position and that theaxis: of 'the said ,pawl '"isJo'i-centerwith relation'to the 'axis of said teeth so that the said pawl will belocated in proper relation to the teeth.

We claim: A

l. An adjustable torque tool including a handle having a shank bearingportion, the said handle having an axial threaded recess therein, areduced portion at the bottom of said threaded recess and an axial boreextending from said reduced recess through the said shank bearingportion, a shank rotatably mounted in said bore and extending from theshank bearing portion of the handle, a ratchet head on said shankrotatable in the reduced recess portion, an annular row of teeth uponthe end of said head, a backing screw member threaded to the wall of thesaid axial recess in the handle and engageable with said head forpreventing longitudinal movement of the shank, the said screw having anoit-center longitudinal bore extending therethrough, a pawl slidable insaid oit-center bore and extending from said backing screw into contactwith the ratchet teeth on said head, a spring urging the pawl into saidcontact, and an adjusting screw also threaded to the wall of the recessin the handle and adjustable longitudinally therein for varying thepressure of the spring member against the pawl.

2. An adjustable torque tool including a handle portion having an axialthreaded recess therein with an internal thread in the wall thereof, areduced portion at the bottom of said recess providing an annularshoulder surrounding the top of said reduced portion, and an axial borecontinuing from the bottom of said reduced portion through the saidhandle, a shank rotatably mounted in said bore and having a headrotatably contained within the reduced recess portion and a plurality ofannularly disposed ratchet teeth in the top of said head, a backingscrew threaded to the said internal thread and engaging the said annularshoulder, the said backing screw having a longitudinal bore extendingtherethrough off-center relatively to the axes of said screw, a pawlslidable in said bore of the screw and extending from the bottom of saidspring member in said bore of the screw urging the pawl in said Contactwith the ratchet teeth, an adjusting screw also threaded to thesaidinternal thread and adapted for varying the pressure of said springupon the pawl, the said adjusting screw extending beyond the upper endof the handle portion, and a locking nut threaded to the said extendingportion of the adjusting screw and abutting the end of the handle forlocking the said adjusting screw in adjusted position.

3. An adjustable torque tool including a handle portion having an axialrecess therein, an internal thread on the `wall of said recess, areducedrrecess portion at the bottom of said threaded Irecess providingan annular shoulder surrounding the top ofsaid recess portion, and anaxial bore continuing from the bottom of said reduced portion throughthe said handle, a 4shank rotatably mounted in said bore and having ahead rotatably contained within the reduced recess portion and aplurality of annularly disposed ratchet teeth in the top of said head,.abacking screw threaded to the said internal thread and engaging the saidannular shoulder, the said backing screw having a longitudinal boreextending there through oit-center relatively to the axes of said screw,a pawl slidable in said bore of the screw and extending from the 'bottomof said screw into engagement with the said ratchet teeth, a springmember in said 'bore of 'the screw urging the pawl into contact with theratchet teeth and extending above the upper end of the screw, anadjusting screw also threaded to the said internal thread and engagingthe projecting end of the said spring for varying the pressure thereofupon the pawl, the said adjusting screw extending beyond the upper endof the i a reduced head portion which extends beyond the end of thehandle and the lock nut is also threaded to the said handle portion, anda locking nut between said adjusting wherein the adjusting screw has anannular shoulder and l internal thread and engages the said shoulder tolock the adjusting screw in adjusted position and has a recess whichreceives the `said head portion.

5. An adjustable torque tool including a handle por.- tion having anaxial recess therein, an internal thread on the wall of said recess, areduced recess portion at the bottom of said threaded recess providingan annular shoulder surrounding the top of `said recess portion, and anaxial bore continuing -from the bottom of said reduced portion throughthe said handle, a shank rotatably mounted in said bore and having ahead rotatably contained within the reduced recess portion and aplurality of annula-rly disposed ratchet teeth in the top of said head,a `backing screw threaded to the said internal thread and engaging thesaid annular shoulder, the said backiug screw having a longitudinal boreextending therethrough ott-center relatively to the axes of said screw,a pawl slidable in said bore of the screw and extending from the bottomof said screw into engagement with the said ratchet teeth, a springmember in said bore of thc screw urging the pawl into contact with theratchet teeth,

"an adjusting screw also threadedpto the said internal thread andadapted for varying the pressure of said spring upon the pawl, and alock nut also threaded to said in- 'ternal thread and engageable withthe said adjusting screw lfor locking it in adjusted position.

References Cited in the tile of this patent UNITED STATES PATENTS1,527,757'. Street Feb. y24, 1925 2,491,325 McVey Dec. 13, 1949 FOREIGNPATENTS Y 256,607 Switzerland Aug. '31, '1948

